Insitute of Physiological Chemistry and Pathobiochemistry, University Hospital Münster, Münster, Germany.
PLoS One. 2012;7(12):e50809. doi: 10.1371/journal.pone.0050809. Epub 2012 Dec 3.
Decorin, a small leucine-rich proteoglycan harboring a dermatan sulfate chain at its N-terminus, is involved in regulating matrix organization and cell signaling. Loss of the dermatan sulfate of decorin leads to an Ehlers-Danlos syndrome characterized by delayed wound healing. Decorin-null (Dcn(-/-)) mice display a phenotype similar to that of EDS patients. The fibrillar collagen phenotype of Dcn(-/-) mice could be rescued in vitro by decorin but not with decorin lacking the glycosaminoglycan chain. We utilized a 3D cell culture model to investigate the impact of the altered extracellular matrix on Dcn(-/-) fibroblasts. Using 2D gel electrophoresis followed by mass spectrometry, we identified vimentin as one of the proteins that was differentially upregulated by the presence of decorin. We discovered that a decorin-deficient matrix leads to abnormal nuclear morphology in the Dcn(-/-) fibroblasts. This phenotype could be rescued by the decorin proteoglycan but less efficiently by the decorin protein core. Decorin treatment led to a significant reduction of the α2β1 integrin at day 6 in Dcn(-/-) fibroblasts, whereas the protein core had no effect on β1. Interestingly, only the decorin core induced mRNA synthesis, phosphorylation and de novo synthesis of vimentin indicating that the proteoglycan decorin in the extracellular matrix stabilizes the vimentin intermediate filament system. We could support these results in vivo, because the dermis of wild-type mice have more vimentin and less β1 integrin compared to Dcn(-/-). Furthermore, the α2β1 null fibroblasts also showed a reduced amount of vimentin compared to wild-type. These data show for the first time that decorin has an impact on the biology of α2β1 integrin and the vimentin intermediate filament system. Moreover, our findings provide a mechanistic explanation for the reported defects in wound healing associated with the Dcn(-/-) phenotype.
核心蛋白聚糖是一种富含亮氨酸的小蛋白聚糖，其 N 端带有一条硫酸皮肤素链，参与调节基质组织和细胞信号转导。核心蛋白聚糖硫酸皮肤素链的缺失会导致埃勒斯-当洛斯综合征，其特征是伤口愈合延迟。核心蛋白聚糖缺失（Dcn(-/-)）小鼠表现出与埃勒斯-当洛斯综合征患者相似的表型。在体外，Dcn(-/-) 小鼠的纤维状胶原表型可以被核心蛋白聚糖拯救，但不能被缺乏糖胺聚糖链的核心蛋白聚糖拯救。我们利用三维细胞培养模型来研究细胞外基质的改变对 Dcn(-/-)成纤维细胞的影响。通过二维凝胶电泳和质谱分析，我们鉴定出波形蛋白是核心蛋白聚糖存在时差异上调的蛋白质之一。我们发现，缺乏核心蛋白聚糖的基质会导致 Dcn(-/-)成纤维细胞的核形态异常。这种表型可以被核心蛋白聚糖聚糖蛋白拯救，但效率较低。核心蛋白聚糖处理导致 Dcn(-/-)成纤维细胞在第 6 天α2β1 整合素显著减少，而核心蛋白聚糖蛋白核心对β1 没有影响。有趣的是，只有核心蛋白聚糖核心诱导波形蛋白的 mRNA 合成、磷酸化和从头合成，表明细胞外基质中的核心蛋白聚糖聚糖蛋白稳定了波形蛋白中间丝系统。我们可以在体内支持这些结果，因为与 Dcn(-/-)相比，野生型小鼠的真皮中含有更多的波形蛋白和更少的β1 整合素。此外，α2β1 缺失的成纤维细胞也显示出与野生型相比，波形蛋白的含量减少。这些数据首次表明，核心蛋白聚糖对α2β1 整合素和波形蛋白中间丝系统的生物学有影响。此外，我们的研究结果为报道的与 Dcn(-/-)表型相关的伤口愈合缺陷提供了一种机制解释。
